This invention relates to multi-piece solid golf balls having excellent flight performance in the high head speed (HS) region intended for professional and skilled golfers, excellent controllability on iron shots and approach shots, and improved durability to repeated impact.
At present, of golf balls having a good balance of superior distance performance in the high head speed region intended for professional and skilled golfers and controllability on iron shots and approach shots, three-piece solid golf balls having a cover inner layer which is hard and a cover outer layer which is made of urethane resin are on widespread use.
Such golf balls are found in U.S. Pat. No. 6,663,507 describing a three-piece solid golf ball in which the intermediate layer and the cover are formed of urethane resins, and the intermediate layer is relatively hard, and U.S. Pat. No. 6,592,470 describing a three-piece solid golf ball in which the cover is made of urethane and the intermediate layer is relatively thick. Other golf balls include the one described in JP-A 6-343718.
In these golf balls, however, the cover is insufficiently improved in durability to repeated impact, with a particular tendency of allowing the intermediate layer to crack.
Also, JP-A 2003-175128 describes a golf ball whose cover has a ternary composite of rubber/polyolefin/nylon components compounded therein. This description does not relate to a golf ball of three-layer structure or make investigation on durability to repeated impact.